externalize db.properties file of activiti-rest war

I have downloaded Activiti 6 and deployed all 3 war files (activit-admin, activiti-app, activiti-rest to tomcat. For database configuration I moved files from "activiti-admin" (activiti-admin.properties) & "activiti-app" (activiti-app.properties) to /tomcat/lib folder. So, for any reason if I have to delete exploded war from webapps directory, i can do that without loosing my database configuration.

But, somehow this does not work with db.properties of activiti-rest war. I copied it to tomcat/lib directory. But it still refers to the one from exploded war file.

Is there a way to externalize this property file, so I won't have to update database settings everytime I delete exploded war and restart server?